In dairy cows, milk yield increases rapidly after parturition until a peak at around wk 6 of lactation. However, the description of the shape of the lactation curve is commonly based on weekly average milk yields. For a more detailed analysis of the milk production curve from the very beginning of lactation including the colostral period and the effect of colostrum yield on further lactational ...

diacylglycerol acyltransferase1 (dgat1) has been introduced as a strong potential candidate gene for milk fat content in cattle. dgat1 gene plays a key role in the final step of triglyceride synthesis. in this study, the genetic variability in the region spanning exon 1 to exon 2 of the buffalo dgat1 gene was investigated by dna sequencing. two hundred buffaloes belonging to three indigenous po...

twenty four primiparous and multiparous holstein cows on early lactation, beginning five weeks postpartum, were used for four weeks to investigate the effects of supplemention of rumen-protected choline (rpc) or vitamin e on milk yield, milk composition, dry matter intake, body condition score and body weight. the cows were randomly assigned to one of the following treatments: i)no supplement (...

understanding cattle metabolism and its relationship with milk products is important in bovine breeding. a systemic view could lead to consequences that will result in a better understanding of existing concepts. topological indices and quantitative characterizations mostly result from the application of graph theory on biological data. in the present work, the enzyme network involved in cattle...

lactoferrin (lf) is a bioactive protein present in all external secretions such as milk that plays important role in the innate host defense. therefore, the lf has a major role in bovine mammary gland defense during mastitis. in this study, 5’-flanking region of bovine lf gene containing three single nucleotide polymorphisms (snps) at positions −602 (t/g), −600 (a/g) and -586 (t/c) were screene...

placental lactogen is a polypeptide hormone that is produced by the placenta, also known as chorionic somatomammotropin hormone. it has both growth hormone and prolactin activities on growth, lactation, and luteal steroid production. the objective of this study was to investigate the bovine placental lactogen (bpl) gene polymorphism of holstein cows in razavi khorasan province. blood samples we...

the aim of this study was to test the genotypes effect of dgat1 gene on breeding value in iranian holstein milk production traits. for this purpose, 103 semen samples of registered bulls were collected and then genotyped for partial region of dgat1 gene. the studied traits were milk yield (my), fat yield (fy), protein yield (py), fat percentage (fp) and protein percentage (pp). first lactation ...

We examined the effect of calving month (CM) on the production of milk and milk protein by Israeli Holstein dairy cows located in the main climatic zone of Israel during their third and fourth lactations, and found it to be significant. Cows that calved in December produced the highest milk and milk protein yields, and those that calved in June produced the lowest, 92.8% of the maximum. The com...

The objective of this research was to partition phenotypic variation in calf gain from birth to weaning, and milk production measured, by the weigh-suckle-weigh method, and udder score of cows into genetic and nongenetic components. Data were from the Line 1 Hereford population maintained by USDA-ARS at Miles City, MT, and included observations of pre-weaning gain (n = 6,835) from 2,172 dams, m...